Research on the energy coupling coefficient of 45# steel and 304 stainless steel under 3.8μm CW laser irradiation

摘要

Experimental research on the energy coupling characteristic of 45# steel and 304 stainless steel under mid- infrared CW laser irradiation is carried out. Based on the classical electromagnetic theory, the theoretical formula of the energy coupling coefficient is derived under ideal condition. In order to obtain the energy coupling coefficient, an experimental system for reflectance measurement is set up by an integrating sphere. The curves about energy coupling coefficient and the temperature variation are measured respectively. The mechanism about the variation of energy coupling coefficient of sample under mid-infrared CW laser irradiation is also discussed. The experimental results show that the energy coupling coefficient of sample increased with temperature rising, but the curve in the heating stage is not consistent with the curve in the cooling stage, which means the change of the energy coupling coefficient is not a reversible process. Combined with the experimental phenomena and the energy dispersive spectrometry, the qualitative analysis about the differences between the 45# steel and 304 stainless steel is presented after irradiation. It indicates that the oxidation reaction has a significant effect on the laser interaction with sample. Accordingly, the variation of coupling coefficient of 304 stainless steel is not as obvious as that of 45# steel.